Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #11   Report Post  
Old April 18th 16, 07:50 AM posted to rec.radio.shortwave
external usenet poster
 
First recorded activity by RadioBanter: May 2011
Posts: 8
Default Kenwood R-1000

On 4/17/2016 4:33 PM, DhiaDuit wrote:
On Sunday, April 17, 2016 at 1:48:00 PM UTC-5, G Cornelius wrote:
On 04/16/2016 04:00 AM, analogdial wrote:
Tubes last alot longer than paper and electrolytic capacitors.


Now there's a blanket statement if I ever heard one.

My experience with the tube era was that a power supply
would commonly have problems with either the rectifier
tube or the electrolytics.

Back then - as a teen, that is - I was a lot better at replacing
tubes and swapping out electrolytics than I was at anything
else, so take this with a grain of salt, but there did seem to
be a lot of tube failures. The tubes that ran hot in the
miniature tube versions of the All American Five radio - the
50C5 output tube and the 35W4 (?) rectifier - were the usual
suspects.

Nowadays tube radios, etc., seem to be showpieces and not
actually used, with those ancient capacitors continuing to
age while the tube filaments remain intact; so, today at
least, the old tubes last way longer than those ancient
capacitors!

George

P.S. The All American Five in my garage is still plugged in
and still works fine at almost 50 years of age. Likely had
a tube or two replaced over the years and little else.


Do you remember that many stores had tube testers and some of those stores sold tubes too? I reckymember them.


I'm old enough to remember those well. I had a beast Hallicrafters short
wave tube radio that I'd stay up much too late listening to. Good memories.
  #12   Report Post  
Old April 18th 16, 09:37 PM posted to rec.radio.shortwave
external usenet poster
 
First recorded activity by RadioBanter: Mar 2012
Posts: 3,217
Default Kenwood R-1000

On Monday, April 18, 2016 at 1:50:57 AM UTC-5, Mike S wrote:
On 4/17/2016 4:33 PM, DhiaDuit wrote:
On Sunday, April 17, 2016 at 1:48:00 PM UTC-5, G Cornelius wrote:
On 04/16/2016 04:00 AM, analogdial wrote:
Tubes last alot longer than paper and electrolytic capacitors.

Now there's a blanket statement if I ever heard one.

My experience with the tube era was that a power supply
would commonly have problems with either the rectifier
tube or the electrolytics.

Back then - as a teen, that is - I was a lot better at replacing
tubes and swapping out electrolytics than I was at anything
else, so take this with a grain of salt, but there did seem to
be a lot of tube failures. The tubes that ran hot in the
miniature tube versions of the All American Five radio - the
50C5 output tube and the 35W4 (?) rectifier - were the usual
suspects.

Nowadays tube radios, etc., seem to be showpieces and not
actually used, with those ancient capacitors continuing to
age while the tube filaments remain intact; so, today at
least, the old tubes last way longer than those ancient
capacitors!

George

P.S. The All American Five in my garage is still plugged in
and still works fine at almost 50 years of age. Likely had
a tube or two replaced over the years and little else.


Do you remember that many stores had tube testers and some of those stores sold tubes too? I reckymember them.


I'm old enough to remember those well. I had a beast Hallicrafters short
wave tube radio that I'd stay up much too late listening to. Good memories.


Vacuum Tube Testers Youtube
  #13   Report Post  
Old April 20th 16, 10:24 PM posted to rec.radio.shortwave
external usenet poster
 
First recorded activity by RadioBanter: Jun 2006
Posts: 487
Default Kenwood R-1000

Michael Black wrote:
I gather those with HRO-500s have had some problem replacing germanium
transistors (and probably the germanium transistors need replacing because
they've gone bad over time).



Germanium transistors are cheap and plentiful on eBay. You need to figure
out which ones made in the Soviet Union replace the ones made in the west.

Germanium transistors were mostly PNP, so NPN ones are harder to find.

Replacements for CK722, 2n404, 2n107 and 2n109 are less than a $.25 each
including postage. I am sure there are others, but those were the ones
I needed.


I found 100 assorted Tesla (eastern Europe, not actually Soviet) ones
for less than $.50 each including postage.

Geoff.

--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379

  #14   Report Post  
Old April 21st 16, 07:23 PM posted to rec.radio.shortwave
external usenet poster
 
First recorded activity by RadioBanter: Mar 2008
Posts: 618
Default Kenwood R-1000

On Wed, 20 Apr 2016, Geoffrey S. Mendelson wrote:

Michael Black wrote:
I gather those with HRO-500s have had some problem replacing germanium
transistors (and probably the germanium transistors need replacing because
they've gone bad over time).



Germanium transistors are cheap and plentiful on eBay. You need to figure
out which ones made in the Soviet Union replace the ones made in the west.

Germanium transistors were mostly PNP, so NPN ones are harder to find.

Replacements for CK722, 2n404, 2n107 and 2n109 are less than a $.25 each
including postage. I am sure there are others, but those were the ones
I needed.

At least some of those are audio bandwidth transistors, the HRO-500 of
course needs transistors good in the shortwave and low VHF segment.

I just know I've seen people writing about restoring their HRO-500s and
other things with germanium diodes, and getting replacements has been some
sort of an issue.

I probably have some germanium transistors around, unless I tossed them.
There was a period in the seventies when the local electronic store, which
also sold surplus (Etco Electronics, they later moved their base to the US
to do mailorder) was offering great deals on germanium transistors, but
their selling point wasn't that they were germanium. It was that they had
good frequency response. I did buy a lot of those back then.

In some ways it is a surprise the HRO-500 could come out in 1964. It's
not that long before that transistors were for audio and at best the AM
broadcast band, yet here is a receiver that from reports is fairly good,
it wasn't a consumer radio, but which could be transistorized. The big
wave of transistor shortwave receivers came towards the end of the
sixties, and some, like my Hallicrafters S-120A, were awful, in part
because they were transistorized. Lots of overload, on top of the usual
issues related to low end receivers.

Michael
  #15   Report Post  
Old April 22nd 16, 03:22 PM posted to rec.radio.shortwave
external usenet poster
 
First recorded activity by RadioBanter: Nov 2015
Posts: 517
Default Kenwood R-1000

G Cornelius wrote:

On 04/16/2016 04:00 AM, analogdial wrote:
Tubes last alot longer than paper and electrolytic capacitors.


Now there's a blanket statement if I ever heard one.

My experience with the tube era was that a power supply
would commonly have problems with either the rectifier
tube or the electrolytics.


Series string sets are harder on tubes than transformer sets. Open
heaters and HK shorts are the usual failures. A thermistor used as an
inrush current limiter helps.

The failure rate for paper caps must be close to 100% by now. That
doesn't mean that the circuit no longer works but that the leakage is
now out of spec and they will only get worse in the future. I doubt
there's been a decent paper wrapped elecrolytic seen for at least 20
years.

I seem to recall reading that some small signal tubes are rated for a
life of 20,000 hours. Or was it 50,000 hours? Anyway, 20,000 hours at
4 hours a day is about 14 years. Maybe twice that long before the radio
actually goes deaf. I like to fix up old radios and I very rarely find
tubes with low gain. As I mentioned, the occasional common failure
modes are open heaters and HK shorts.

I have a strong suspicion that most of the tubes replaced in the past
were still useable. A gently aging tube might work quite well at normal
voltages but be an underperformer in a circuit in which a leaky screen
bypass cap is pulling down the voltage. A new tube might perk up the
circuit but the real problem is the leaky cap.

And it was common repair shop practice to knowingly replace good parts
such as tubes.

Shocking, I know! And I understand why. I was a new tech at a shop,
and a customer called in about her microphone preamp all of the sudden
having distorted sound. I asked the obvious question "Did you put new
batteries in?" "Yesssss! Of course I put new batteries in!!!!!!!! Do
"you think I am an idiot??!!!"

Needless to say, her "new" batteries were just as dead as the first set.

Stupid me, I thought she'd be pleased that new batteries that actually
worked brought the preamp back to perfect operation.

"YOU CHARGED ME THAT MUCH (our minimum charge, actually pretty cheap)
JUST TO REPLACE THE BATTERIES!! YOU'RE A DAMN CROOK!!!!"

No, if I was a crook, I could have charged her five times as much for
replacing good parts and we both would have been so much happier that
day.

Long story short, tubes get an largely undeserved bad rap for
unreliability.




  #16   Report Post  
Old April 22nd 16, 07:37 PM posted to rec.radio.shortwave
external usenet poster
 
First recorded activity by RadioBanter: Mar 2008
Posts: 618
Default Kenwood R-1000

On Fri, 22 Apr 2016, analogdial wrote:

G Cornelius wrote:

On 04/16/2016 04:00 AM, analogdial wrote:
Tubes last alot longer than paper and electrolytic capacitors.


Now there's a blanket statement if I ever heard one.

My experience with the tube era was that a power supply
would commonly have problems with either the rectifier
tube or the electrolytics.


Series string sets are harder on tubes than transformer sets. Open
heaters and HK shorts are the usual failures. A thermistor used as an
inrush current limiter helps.

The failure rate for paper caps must be close to 100% by now. That
doesn't mean that the circuit no longer works but that the leakage is
now out of spec and they will only get worse in the future. I doubt
there's been a decent paper wrapped elecrolytic seen for at least 20
years.

And the stuff wasn't intended for perpetual use. It was "average stuff"
intended to be used, and then eventually fade away. Indeed, it was
tossed. SSB came along, making a lot of stuff "obsolete", transistors
came along and people wanted that. So in the late sixtes and early
seventies, the old AM and tube equipment was relatively cheap. There was
a period when I was getting stuff, playing with it a bit, then trading it
for something else. Not many were thinking of "collecting", and nostalgia
hadn't set in. So that generally caused the stuff to be relegated to the
garbage, or the top shelf.

It's only in more recent times that the stuff was seen as valuable. So
those capacitors that weren't so great to begin with are now decades
older. The tubes sitting around didn't age (though I finally stripped
some old RCA Carfones, mobile equipment for the trunk of the car, and when
I pulled the tubes, a fair number had been broken, even though I don't
remember them being in a situation for that, they just sat there for
decades), while the capacitors probably kept on aging even when not in
use.

As I said, it's the way they made capacitors up to a certain point,
equipment made after that point didn't use paper capacitors but did use
ceramic, so their life is likely in good shape now.

Michael
  #17   Report Post  
Old April 23rd 16, 07:34 PM posted to rec.radio.shortwave
external usenet poster
 
First recorded activity by RadioBanter: Nov 2015
Posts: 517
Default Kenwood R-1000

Michael Black wrote:


And the stuff wasn't intended for perpetual use. It was "average stuff"
intended to be used, and then eventually fade away. Indeed, it was
tossed. SSB came along, making a lot of stuff "obsolete", transistors
came along and people wanted that. So in the late sixtes and early
seventies, the old AM and tube equipment was relatively cheap. There was
a period when I was getting stuff, playing with it a bit, then trading it
for something else. Not many were thinking of "collecting", and nostalgia
hadn't set in. So that generally caused the stuff to be relegated to the
garbage, or the top shelf.

It's only in more recent times that the stuff was seen as valuable. So
those capacitors that weren't so great to begin with are now decades
older. The tubes sitting around didn't age (though I finally stripped
some old RCA Carfones, mobile equipment for the trunk of the car, and when
I pulled the tubes, a fair number had been broken, even though I don't
remember them being in a situation for that, they just sat there for
decades), while the capacitors probably kept on aging even when not in
use.

As I said, it's the way they made capacitors up to a certain point,
equipment made after that point didn't use paper capacitors but did use
ceramic, so their life is likely in good shape now.

Michael


The caps probably did age even when not in use. I had some old NOS wax
dipped paper caps and they all were leaky. Somewhere in Terman's Radio
Engineer's handbook, he says paper caps can be expected to work as new
for only a few years or so. He had an example for leakage sensitive
circuits in which the usual coupling cap is replaced by two much
larger caps in series with a grounded bleeder in between which,
presumably, would forestall the capacitor aging problem.

Back in the 50s, the higher quality, less disposable electronics, used
those newfangled Sprague Black Beauty capacitors in place of the run
of the mill wax dipped paper caps. I suppose that toxic, short circuit
mess hadn't fully devloped by the mid 60s, when Sprague retained the
name "Black Beauty" for their axial lead mylar film caps. The "Orange
Drop" name for radial lead caps is still around, of course.

Mylar caps replaced paper caps at about time electronics started going
solid state so it's understandable why people associate the unrelibility
problems with tubes.


  #18   Report Post  
Old April 27th 16, 12:14 AM posted to rec.radio.shortwave
external usenet poster
 
First recorded activity by RadioBanter: Jun 2006
Posts: 487
Default Kenwood R-1000

Michael Black wrote:
At least some of those are audio bandwidth transistors, the HRO-500 of
course needs transistors good in the shortwave and low VHF segment.


I expect they are there too. The ones I am interested are for yellow
boxes made around 1963 which use audio transistors. Most of them are
either oscillators to boost DC voltage, some are dc amplifiers.


I just know I've seen people writing about restoring their HRO-500s and
other things with germanium diodes, and getting replacements has been some
sort of an issue.


The Soviet D9b diodes make great detectors and are about a penny each,
including postage. They were half that because the lower case b in the
Cyrilic (Russian) alphabet looks like a number 5, and they were listed
as D95 diodes, which no one could find any specs on.

I think I had something to do with the price rise, when I commented on
the price on several groups, the listings were fixed and the price went up.

There even are 1n34a diodes still made with germanium in them. Most of the
so called germanium diodes are actualy silicon. They make finding the
real ones difficult as eBay vendors don't differentiate.

I have a few UK germanium diodes, that have real gold in them, and are
much better detectors. I found them on eBay for 1 UKP each. I am saving
them for a special project, when I think of it.


I probably have some germanium transistors around, unless I tossed them.
There was a period in the seventies when the local electronic store, which
also sold surplus (Etco Electronics, they later moved their base to the US
to do mailorder) was offering great deals on germanium transistors, but
their selling point wasn't that they were germanium. It was that they had
good frequency response. I did buy a lot of those back then.


If you can look up what they were, I would be interested in finding out.

Geoff.


--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379

Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
WTB: Kenwood R-1000 Steve Boatanchors 0 January 6th 07 09:37 PM
Kenwood R-1000 DJ Shortwave 0 January 6th 07 04:14 AM
WTB: Kenwood R-1000 [email protected] Swap 0 July 8th 06 12:47 AM
Kenwood R-1000 SR Shortwave 4 September 1st 05 08:13 PM
Kenwood R-1000 vs. Sat 800 Frank Simmons Shortwave 0 November 26th 03 05:21 PM


All times are GMT +1. The time now is 09:59 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017